The present invention relates to polymorphic forms of (1-{3-[3-(4-cyano-3-methoxy-phenyl)ureido]-phenyl}-ethyl)-carbamic acid-2-cyano-1-ethyl-ethyl ester having the structure below (hereinafter “Compound 1”):

The present invention also relates to processes to prepare polymorphic forms of Compound 1.
Compound 1 is a potent IMPDH inhibitor useful in treating IMPDH-mediated diseases. Compound 1, compositions thereof, and methods therewith are disclosed in U.S. Pat. No. 6,498,178 B2 (hereinafter “the '178 patent”), the entire disclosure whereof is incorporated herein by reference.